Dec 21, 2012

`SOME INTERESTING FACTS ABOUT EARTH- COMPILED BY Dr.KESIRAJU RAMPRASAD


SOME INTERESTING FACTS ABOUT EARTH



1. The Earth Is Not Round



No, no – I'm not a member of the Flat Earth Society. The Earth is a sphere, but due to its gravitational forces it is not a perfect circle. In fact, there is a bulge around the equator because of this. The Earth's Polar radius is 3,949.99 miles, while its Equatorial radius is 3,963.34 miles. That's right: the Earth has love handles.



It's not a perfect sphere. As Earth spins, gravity points toward the center of our planet (assuming for explanation's sake that Earth is a perfect sphere), and a centrifugal force pushes outward. But since this gravity-opposing force acts perpendicular to the axis of Earth, and Earth's axis is tilted, centrifugal force at the equator is not exactly opposed to gravity. This imbalance adds up at the equator, where gravity pushes extra masses of water and earth into a bulge, or "spare tire" around our planet




On the Move
You may feel like you're standing still, but you're actually moving — fast. Depending on where you are on the globe, you could be spinning through space at just over 1,000 miles per hour. People on the equator move the fastest, while someone standing on the North or South pole would be perfectly still. (Imagine a basketball spinning on your finger. A random point on the ball's equator has farther to go in a single spin as a point near your finger. Thus, the point on the equator is moving faster.)
(Photo shown here, a true-color image taken on May 5, 2000, by an instrument aboard NASA's Terra spacecraft, over the North Pole, with sea ice shown in white and open water in black.)


Oh yeah, and the Earth isn't just spinning: It's also moving around the sun at 67,000 miles (107,826 km) per hour.


It's Old
Researchers calculate the age of the Earth by dating both the oldest rocks on the planet and meteorites that have been discovered on Earth (meteorites and Earth formed at the same time, when the solar system was forming). Their findings? Earth is about 4.54 billion years old.
(Photo shown here, what may be the oldest known rocks on Earth, called the Nuvvuagittuq Belt on the coast of the Hudson Bay in Northern Quebec,
and dating back to 4.28 billion years ago, scientists estimate.)


Gets Recycled
The ground you're walking on is recycled. Earth's rock cycle transforms igneous rocks to sedimentary rocks to metamorphic rocks and back again. The cycle isn’t a perfect circle, but the basics work like this: Magma from deep in the Earth emerges and hardens into rock (that's the igneous part). Tectonic processes uplift that rock to the surface, where erosion shaves bits off. These tiny fragments get deposited and buried, and the pressure from above compacts them into sedimentary rocks such as sandstone. If sedimentary rocks get buried even deeper, they "cook" into metamorphic rocks under lots of pressure and heat. Along the way, of course, sedimentary rocks can be re-eroded or metamorphic rocks re-uplifted. But if metamorphic rocks get caught in a subduction zone where one piece of crust is pushing under another, they may find themselves transformed back into magma.


Hot Spot
The fiery award for Earth's hottest spot goes to El Azizia, Libya, where temperature records from weather stations reveal it hit 136 degrees Fahrenheit (57.8 degrees Celsius) on Setp. 13, 1922, according to NASA Earth Observatory. There have likely been hotter locations beyond the network of weather stations. (The image was created from data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite.)



Creeping Magnetic Pole
Earth has a magnetic field because of the ocean of hot, liquid metal that sloshes around its solid iron core, or that's what geophysicists are pretty certain is the cause. This flow of liquid creates electric currents, which, in turn, generate the magnetic field. Since the early 19th century, Earth's magnetic north pole has been creeping northward by more than 600 miles (1,100 kilometers), according to NASA scientists. The rate of movement has increased, with the pole migrating northward at about 40 miles (64 km) per year currently, compared with the 10 miles (16 km) per year estimated in the 20th century.


Pole Flip-Flops
In fact over the past 20 million years, our planet has settled into a pattern of a pole reversal about every 200,000 to 300,000 years; as of 2012, however, it has been more than twice that long since the last reversal. These reversals aren't split-second flips, and instead occur over hundreds or thousands of years. During this lengthy stint, the magnetic poles start to wander away from the region around the spin poles (the axis around which our planet spins), and eventually end up switched around, according to Cornell University astronomers


Once a Supercontinent
The Earth's continents are thought to have collided to become supercontinents and broken apart again several times in Earth's 4.5 billion year history. The most recent supercontinent was Pangaea, which began to break apart about 200 million years ago; the landmasses that comprised Pangaea eventually wandered into the current configuration of continents.








2. The Name “Earth” Comes From Anglo-Saxons


Every other planet in our solar system is named after a Greek or Roman God, except our planet. The word Earth comes from the Anglo-Saxon word Erda, which means “ground” or “soil” and is thought to be 1,000 years old. Ironically, the planet is covered by 71% water -- the only planet we know of in the entire universe to have this precious fluid in liquid form.

3. There Are Not 24 Hours In a Day


People often claim there aren't enough hours in the day and they're right – not even 24. That's right, the actual time it takes the planet to rotate on its axis is 23 hours 56 minutes and 4 seconds. This is what's called a sidereal day. The solar day, the time it takes for the sun to return to the same spot on the meridian, varies as much as 16 minutes throughout the year, due to the position in its orbit. (Don't ask us to explain how we figure out what time it is, we'll leave that to the nerds in the comments section.)

4. Earth Is The Only Planet With Plate Tectonics


Scientists believe the Earth is made up of 7 major plates of “crust,” which move in different directions up to 4 inches per year. When they crash into each other, the theory goes, mountains are born; where they pull apart we have valleys. On the scary side these also cause earthquakes and volcanoes. The good news is that all this activity allows for carbon -- essential to our very existence -- to be recycled and replenished, allowing life as we know it to continue.

5. Earth Had a Twin Planet Called Theia


Scientists now believe that we were once not alone in our orbit around the Sun – we had a “twin” planet we call Theia, which was the size of Mars and was 60 degrees either in front or behind our Big Blue Ball. One afternoon about 4.533 billion years ago, Theia crashed into the Earth; most of the planet was absorbed, but a large chunk blew off and combined with materials from our planet to create the Moon. Why do we think this? It's because our Moon is unusually large for a planet of our size and has metallic isotopes similar to those on Earth.

6. The Mysterious Moon's (Almost) Perfect Orbit


Speaking of the Moon (and that is its official name) one thing is for sure: it is NOT made of cheese. Aside from that, there are some things we don't know. For example, the lunar center is 6,000 feet closer to the Earth, which should cause its orbit to be more wobbly/erratic, yet it is almost perfectly circular. The Moon is covered in a dust that strangely smells like gunpowder, even though they are completely different materials. Also, while there is no “dark side” of the moon, the Earth's gravitational force has caused the Moon to stop rotating so that only one side faces us. In addition, it's quite an incredible coincidence that the Sun happens to be both 400 times bigger than the Moon and also 400 times farther away from Earth, making them appear the same size in the night sky.

7. The Oceans are over 90% Unexplored


So we've (allegedly) been to the Moon and to Mars, but guess what? We have barely begun to visit the depth of our vast oceans. In fact, less than 10% of the deep blue seas have been explored. The ocean contains 97% of our water and 99% of the living area. While we have identified 212,906 marine species, there are possibly 25 million more that we DON'T know about. Suddenly, the Loch Ness Monster doesn't seem so far-fetched.

8. Coldest Temperature: -128.6 F


While the coldest place on Earth is Antarctica (-100 degrees F) the coldest spot was recorded on July 21, 1983 at Vostok Station in Russia, where sensors recorded –128.6 degrees F. (That's a cold summer!) The hottest spot recorded? On Sept. 13, 1922 El Azizia, Libya registered 136 degrees F.

9. Highest Point on Earth Is Not Mount Everest


True, it's one of the most famous mountains in the world, and at 29,035 ft. above sea level it's pretty darn tall. However, considering we now know that the Earth is not round (see #1), anyone or anything along the equator is slightly closer to the stars. This means that although Mount Chimborazo in Ecuador is just 20,564 ft. above sea level, because it is on this “bump” it is technically further away from the Earth's center (i.e. “higher”) than Everest by 1.5 miles!.

Atmosphear



The Earth’s atmosphere extends out to 10,000 km
The atmosphere is thickest within the first 50 km or so, but it actually reaches out to about 10,000 km above the surface of the planet. This outermost layer of the atmosphere is called the exosphere, and starts about 500 km above the surface of the Earth. As we said, it goes all the way up to 10,000 km above the surface. At this point, free-moving particles can actually escape the pull of Earth’s gravity, and be blown away by the Sun’s solar wind.
But this high atmosphere is extremely thin. The bulk of the Earth’s atmosphere is down near the Earth itself. In fact, 75% of the Earth’s atmosphere is contained within the first 11 km above the planet’s surface.






Many layers of atmosphere coat our planet including the mesosphere, ionosphere, exosphere, and the thermosphere, but it’s the troposphere, closest to the planet itself, that supports our lives and is, in fact, the thinnest at only about 10 miles high.






Believe it or not, most of the Earth’s deserts are not composed entirely of sand. Much, about 85% of them, are rocks and gravel. The largest, the Sahara, fills about 1/3 of Africa (and it is growing constantly) which would nearly fill the continental United States

THE BIG BLUE MARBLE

The earth is, in fact, not really round. It is called an ablate spheroid meaning it’s slightly flattened on the top and bottom poles.
Salty Oceans

If you could evaporate all the water out of all the oceans and spread the resulting salt over all the land on Earth, you would have a five hundred-foot layer coating everything

6. Lakes and Seas
The largest inland sea (or, sometimes called a lake) is the Caspian Sea which is on the border of Iran and Russia.


                          
Our home, Earth, is the third planet from the sun and the only world known to support an atmosphere with free oxygen, oceans of liquid water on the surface and — the big one — life.


Earth Facts –The Blue Planet



·         Earth is referred to as the BLUE PLANET. WHY? Because from space, the oceans combined with our atmosphere make our planet look blue. .
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·         It is the only planet whose name has not been derived from the Roman or Greek mythology? The name has originated from the 8th century Anglo Saxon word- Erda. This means ground or soil .
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·         More than 80% of the earth's surface is volcanic.
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·         The Earth is known by many names - Herda,Erda,Dharti,Jord,,Gaiya,Hlodyn,Jord are few of these examples.
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·         The we shrank Earth's history in 24 hours, we human beings would appear only in lasr two minutes. It tells that the Earth was present in this universe much before the human beings .
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·         The Sun is 333,000 times as large as our earth.
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·         The temperature of earth's inner core is as high as 7000 degrees ,which is even more than the temperature on the surface of the Sun .
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·         Only 11 percent of the earth's surface is used to grow food. .
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·         70% of the Earth’s surface is covered in water. .
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·         Planet Earth rotates around the Sun at approximately 1000 miles per hour. .
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·         The Earth is like a great big magnet,so it pulls everything towards it. This pulling force of earth is called gravity. .
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·         Earth doesn’t take 24 hours to rotate on its axis.It’s actually 23 hours, 56 minutes and 4 seconds. .
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·         A year on Earth isn’t 365 days .It’s actually 365.2564 days. It’s this extra .2564 days that creates the need for leap years. .
·         Earth has 1 moon and 2 co-orbital satellites .
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·         Oceans occupy nearly 71 percent of the surface of earth .
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·         Ten percent of the earth's surface is covered by ice .
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·         The deepest part of the Earth is Pacific Ocean , it is called the Mariana Trench. It is deeper than Mount Everest is high! .
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·         Earth is the third planet from the Sun. This is also the fifth largest planet in the entire solar system.Earth is the only planet known to have life.
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·         The air on earth consists of around 78 percent nitrogen with 21 percent oxygen. This air also contains 1 percent of other ingredients.
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·         The temperature of the earth's interior increases by 1 degree every 60 feet down.
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·         It takes eight and a half minutes for light to get from the sun to earth.
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·         Geology is the study of the rocks that form the planet’s surface. Geologists examine rocks to find out about the history of the Earth and how Earth was formed.
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·         Mount Everest is the highest mountain on Earth and its peak is 8848 meters above sea level. And amazingly it is gaining height
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·         April 22 ,every year is celebrated as Earth Day.April 22 is the first official day of Spring in the Northern hemisphere and of Fall in the Southern hemisphere and was chosen to be Earth Day for this reason
·         The Earth’s atmosphere is composed mainly of nitrogen (77%), oxygen (21%), argon (.93%), and carbon dioxide (0.03%).
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·         Earth has 3 layers,Crust (upper part),Mantle(middle part) & Core (inner-most part),out of these Crust is the lightest.
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·         Seismometer is the device with which earth-quackes is measured.Richter scale shows intensity of earth-quake -that is how strong the waves are on seismometer.
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·         Antarctica is world's longest glacier.
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·         The Earth's equatorial circumference (40,075 km) is greater than its polar circumference (40,008 km..
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·         The highest recorded temperature on Earth is 136°F (58°C) in Libya in 1922..
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·         The lowest recorded temperature on Earth is -128.6°F (-89.6°C) in Antarctica in 1983.
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·         One fifth of land surface is covered by deserts
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·         Astronomy is study of outer space , a person who works in this field is known as astronomer.
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·         Nicolaus Coppenicus was ,the astronomer, who first realized that earth moves round the sun.





Earth is mostly iron, oxygen and silicon
If you could separate the Earth out into piles of material, you’d get 32.1 % iron, 30.1% oxygen, 15.1% silicon, and 13.9% magnesium. Of course, most of this iron is actually down at the core of the Earth. If you could actually get down and sample the core, it would be 88% iron. 47% of the Earth’s crust consists of oxygen.



( I have received a mail my friend. I have added some more information.)

COMPILED
Dr.Kesiraju Ramprasad
Educational psychologist.